Tags field

Adding a list of things to a record is something we need to do pretty frequently; that's why having the tags field is helpful.

field :skills, as: :tags

Options

-> suggestions

You can give suggestions to your users to pick from which will be displayed to the user as a dropdown under the field.

# app/avo/resources/course_resource.rb
class CourseResource < Avo::BaseResource
  field :skills, as: :tags, suggestions: -> { record.skill_suggestions }
end

# app/models/course.rb
class Course < ApplicationRecord
  def skill_suggestions
    ['example suggestion', 'example tag', self.name]
  end
end

Default

[]

Possible values

The suggestions option can be an array of strings, an object with the keys value, label, and (optionally) avatar, or a lambda that returns an array of that type of object.

The lambda is run inside a RecordHost, so it has access to the record along with other things (check the link).

# app/models/post.rb
class Post < ApplicationRecord
  def self.tags_suggestions
    # Example of an array of more advanced objects
    [
      {
        value: 1,
        label: 'one',
        avatar: 'https://images.unsplash.com/photo-1560363199-a1264d4ea5fc?ixlib=rb-1.2.1&ixid=MnwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&auto=format&w=256&h=256&fit=crop',
      },
      {
        value: 2,
        label: 'two',
        avatar: 'https://images.unsplash.com/photo-1567254790685-6b6d6abe4689?ixlib=rb-1.2.1&ixid=MnwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&auto=format&w=256&h=256&fit=crop',
      },
      {
        value: 3,
        label: 'three',
        avatar: 'https://images.unsplash.com/photo-1560765447-da05a55e72f8?ixlib=rb-1.2.1&ixid=MnwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&auto=format&w=256&h=256&fit=crop',
      },
    ]
  end
end

-> dissallowed

The `disallowed` param works similarly to `suggestions`. Use it to prevent the user from adding specific values.

field :skills,
  as: :tags,
  disallowed: ["not", "that"]

Default

[]

Possible values

An array of strings representing the value that can't be stored in the database.

-> enforce_suggestions

Set whether the field should accept other values outside the suggested ones. If set to `true` the user won't be able to add anything else than what you posted in the `suggestions` option.

field :skills,
  as: :tags,
  suggestions: %w(one two three),
  enforce_suggestions: true

Default

false

Possible values

true, false

-> suggestions_max_items

Set of suggestions that can be displayed at once. The excessive items will be hidden and the user will have to narrow down the query to see them.

field :skills,
  as: :tags,
  suggestions: %w(one two three),
  suggestions_max_items: 2

Default

20

Possible values

Integers

-> close_on_select

Set whether the `suggestions` dropdown should close after the user makes a selection.

field :items,
  as: :tags,
  suggestions: -> { Post.tags_suggestions },
  close_on_select: true

Default

false

Possible values

true, false

-> acts_as_taggable_on

Set the field the `acts_as_taggable_on` is set.

Default

nil

Possible values

Any string or symbol you have configured on your corresponding model.

-> disallowed

#### Default

false

Possible values

true, false

-> delimiters

Set the characters that will cut off the content into tags when the user inputs the tags.

field :skills,
  as: :tags,
  delimiters: [",", " "]

Default

[","]

Possible values

[",", " "]

Valid values are comma , and space .

-> mode

By default, the tags field produces an array of items (ex: categories for posts), but in some scenarios you might want it to produce a single value (ex: dynamically search for users and select just one). Use mode: :select to make the field produce a single value as opposed to an array of values.

field :skills,
  as: :tags,
  mode: :select

Default

nil

Possible values

Valid values are nil for array values and select for a single value.

-> fetch_values_from

There might be cases where you want to dynamically fetch the values from an API. The fetch_values_from option enables you to pass a URL from where the field should suggest values.

This options works wonderful when used in Actions.

field :skills,
  as: :tags,
  fetch_values_from: "/avo/resources/skills/skills_for_user"

When the user searches for a record, the field will perform a request to the server to fetch the records that match that query.

Default

nil

Possible values

Valid values are nil, a string, or a block that evaluates to a string. The string should resolve to an enddpoint that returns an array of objects with the keys value and label.

app/controllers/avo/skills_controller.rb

class Avo::SkillsController < Avo::ResourcesController
  def skills_for_user
    skills = Skill.all.map do |skill|
      {
        value: skill.id,
        label: skill.name
      }
    end
    render json: skills
  end
end

config/routes.rb

Rails.application.routes.draw do
  # your routes

  authenticate :user, ->(user) { user.is_admin? } do
    mount Avo::Engine, at: Avo.configuration.root_path
  end
end

if defined? ::Avo
  Avo::Engine.routes.draw do
    scope :resources do
      # Add route for the skills_for_user action
      get "skills/skills_for_user", to: "skills#skills_for_user"
    end
  end
end

INFO

When using the fetch_labels_from pattern, on the Show and Index views you will see the id of those options instead of the label. That is expected, because you are storing the ids in the database and the field can't know what labels those ids have.

To mitigate that use the fetch_labels option.

-> fetch_labels

The `fetch_labels` option allows you to pass an array of custom strings to be displayed on the tags field. This option is useful when Avo is displaying a bunch of IDs and you want to show some custom label from that ID's record.

field :skills,
  as: :tags,
  fetch_values_from: "/avo/resources/skills/skills_for_user",
  fetch_labels: -> {
    Skill.where(id: record.skills).pluck(:name)
  }

In the above example, fetch_labels is a lambda that retrieves the names of the skills stored in the record's skills property.

When you use fetch_labels, Avo passes the current resource and record as arguments to the lambda function. This gives you access to the hydrated resource and the current record.

Default

Avo's default behavior on tags

Possible values

Array of strings

PostgreSQL array fields

You can use the tags field with the PostgreSQL array field.

# app/avo/resources/course_resource.rb
class CourseResource < Avo::BaseResource
  field :skills, as: :tags
end

# db/migrate/add_skills_to_courses.rb
class AddSkillsToCourses < ActiveRecord::Migration[6.0]
  def change
    add_column :courses, :skills, :text, array: true, default: []
  end
end

Acts as taggable on

One popular gem used for tagging is acts-as-taggable-on. The tags field integrates very well with it.

You need to add gem 'acts-as-taggable-on', '~> 9.0' in your Gemfile, add it to your model acts_as_taggable_on :tags, and use acts_as_taggable_on on the field.

# app/avo/resources/post_resource.rb
class PostResource < Avo::BaseResource
  field :tags,
    as: :tags,
    acts_as_taggable_on: :tags,
    close_on_select: false,
    placeholder: 'add some tags',
    suggestions: -> { Post.tags_suggestions },
    enforce_suggestions: true,
    help: 'The only allowed values here are `one`, `two`, and `three`'
end

# app/models/post.rb
class Post < ApplicationRecord
  acts_as_taggable_on :tags
end

That will let Avo know which attribute should be used to fill with the user's tags.

Related

You can set up the tags as a resource using this guide.

Array fields

We haven't tested all the scenarios, but the tags field should play nicely with any array fields provided by Rails.

# app/avo/resources/post_resource.rb
class PostResource < Avo::BaseResource
  field :items, as: :tags
end

# app/models/post.rb
class Post < ApplicationRecord
  def items=(items)
    puts ["items->", items].inspect
  end

  def items
    %w(1 2 3 4)
  end
end